Range finder for photographic cameras



Nov. 9, 1954 C. E. SMITH E' AL RANGE FINDER FOR PHOTOGRAPHIC CAMERAS Filed Dec. l2, 1950 20 M s i "/40 "I ri@ 3 Sheets-Sheet l ATTORNEY IN VEN TOR. CLARENCE E SM/ 771 7' NERW//V HUBER /vD M/L F ORD B.

MOORE Nov. 9, 1954 c. E. SMITH Er AL 2,693,744

RANGE FINDER FOR PHOTOGRAPHIC CAMERAS I Filed Dec. 12, 195o 3 Sheets-Sheet 2 vill/lq I-ulm VII/11111111?) I IN VENT 0R.

@LA/FENCE 5. sM/r HUBERT NEW//V BY un .4l/FORD 8. MOORE Arronwer /l/L Nov. 9, 1954 c. E. SMITH ET A1. 2,693,744

RANGE FINDER FOR PHOTOGRAPHIC CAMERAS Filed Dec. l2, 1950 3 Sheets-Sheet 3 BY A MIL/:ORD 8 MOORE Arron/ver /?L\ United States Patent O RANGEFINDER FOR iPH()IOGRAPHIClCAMERAS i of fDel'ware- L f Application Decembenll;l 1950;I Serial--No. 200,f41'4 4 Claims...-(Cl. 95'-44) 1 Thpresentfinventionfrelates? to -`range iinde'r'sfandmore f particularlyto coupled rangey vindersv'for photographic It is! commonpracticeto attach ai-range "finderto av camerasothatthecamera may properly :be tocused'u'ponv the'objectwhichfisto bephotographed. Conventional attachedrange tindersfhave 'two' mirrorsfr disposedI vertically f one above theI otherfthev yupper mirror beingexed and being ofthe semi-transparent type,'and the lower mirror being 'rotatable and lbeing coupl'edtto the lens'bo'ard,-or

supportfor the front lensy of the camera, so that when` the lenslfboard 'or' support'is movedin or out along the camera bedthe lower mirror is -swungon its axis-of rotationjfl The'user, upon'looking yinto the'eye piece of the"'range finder, seesv two images -of the object to be photographed, one reected from the' lower mirror and the-rear face' 'of the'upper-mirror, andthe other visible directly through the transparentupper mirror.

or back these twovirnages' maybe brought together; and when this is done the camera is in proper focus.l

To rotate the lower mirrorrupon adjustment ofv thef By adjusting the l'ensboard` or .supportlofthe camera forward lens board'or'l supportg'complicatedi lever systems are rei quiredin conventional .i to the cost of the range'fnderand increases the l1kel1 hood of. the range finder-getting. out-of adjustment. z

Moreover,'it has heretoforebeen the practice to-'rnount` the mirrors directly on the'casing of the rangetnder :and-y to secure 'that'fcasing directly to the boxy or housing .of'

the camera.y As ajresult, expansion orcontraction of the 45 camera vhousing or of the rangender casingvatfectsthe attachedrrange iin'clers; lThese'add mirror position, introducing errors which vcan .affectI the,

precision of focusing of the camera.

In conventional'rangefnders;alsoylt is always :dif-f.

iicult to position both mirrorsv so that Atheywmay lie in parallel planes.'l

lIf the planecof one 'mirror is slightly tiltedv7 w with-'reference `to the plane of the othermirror, lhowever, f

side'. image will be'caused.-y This is always confusing and obstructs-ecient use ofathe rangenden .In conventional frange.nders,ifurthermore, the mirrors are cemented-to their supports or backings. entirely satisfactory.

One object of :the present invention is'to providel a rangeiinderwhich willbe much simpler in constructionA than prior known rangefnders."

Another object of the invention is to provide a coupled rangender attachment for This is a messy job andfnot ,60 photographic cameras having a simpler. coupling mechanism between .the front-lens and the rngender than .has heretofore been employed... A

Another object of the invention is to provide a'rangenderattachment for photographic lcameras'in which the lowermirror is fixed and the upper transparent; mirror is made rotatable.

A further objectof the invention is to provide an improved` mounting for vthe window of a range .finder attachment *whichr will"permit of' quickly insertingy or `removing awindow from its mounting.

A st ll further object'ofk the invention is to provide a mounting for the xed mirrorwhich will permit of readily adjustingl'the plane off-that vmirror to beparallel to the plane of lthe rotatable mirror therebyto avoid side image.

Still otherobjects of the'nvention' are to provide a rangender' for attachment" to a photographic. camera which lwilll be more 'durable than' conventional rangeA finders and ymore ystabletherebyinsuring greater 'accuracy and :longer life.1

Other objects of the inventionwillbe apparentA herein'-U after from the-specictiolrfandgfrorr the Yrecital of the` appended claims. In the drawings:

Fig.' l is a side=eleva`tionof-acamera inlopen position'` and v4showing attachedi'thereto a rangendr -constructed according yto 'one embodiment Iofv this invention; Fig.-2is aview onan enlarged'scale 'ofthe' range nderwith the outside 'cover of the rangendr removed and with parts shown in section;

Fig.`=3 is a section through the*i'a'ngefinderlftakenl at right angles to fthe" view `of Fig. I*2;

Fig."5 isaffrag'rnenta'ryfv detail viewfshowing the con-f nection betweenfthefobje'ctive slide-of the camera Yand the 'shafton whicli'- the rotatab1e= mirror is mounted;

Fig. 6 is a fragmentary horizontal section' through'the camera box further showing the connection between-ob-y jective 'slide and the 'mechanism which rotates'l the trans.

parent mirror; y

Fig. 7 is a front elevation of theserparts; Fig. 8 is a sectionif'on enlarged'scale;

Figs'. A9v and `y-l() are 'detailfviews'takeniat right` angles` to onetanother and'y showing :the I'mountingof the lower"- mirrorl of the range finder;

Figf'll is ai'fragrnentary section showingthe manner and `means by whicli'each'mirroris secured'zto its mountlng; 1 Y

Fig. l2 is a section on thelinei-12=`-*12'of'FigQf3' look-A i ing in `the `drection'of -the Yarrowsfand' on an .enlarged scale;

Fig" 13 is'K a 'fragmentary section: on vthe :line4 1'3-13/ of Figli4 looking in the directiontofthearrows andrshwl mounting of one. of thewindows of the range' ing the finder; 'and Fig-"I4 is afperspective'view'of oneof 'the used=in fthe window'mounting. r

Referring -now` to the ldrawingsby. numerals of refer'- ence, 20 denotes t-hecase or -boxfof aconventional camera, and 22 'denotes the bedof thiscameraz'v This' bed'is hinged to the 'ca'meratbox or casing 20f'and is held/Sinioperative I position by side'farms23. "i

shown )21' f- ThehfrailSjJ-ZS and' '29" are mounted'l Yt'o slide. in

the camerafboxfZOJand'onthe bedflz;` respectively. -Thus', any movement `imparted "to2 the rrai1s. `28i stransmittedy to the rails 29 causingthemlto travel'in the guideways 30 as usua1 iby ak focusingu pinions :(not shown):.which' engage in conventional .mannen One rail..29 has .a dove tailed'grove 40.1(Figs. 6 and 7) formedrin'it' .Mouutedinthis groovelsV a corre i V41.1.' Secured toth'is-block as by means of screws .42 is a'right angular.shapedbracket 44.

upright portion of this Abracket fthreaded to receive an adjustableLA screwor follower "47. 'i This follow'erengages the peripheralsurface' 149 ofA one rlobe'ofav cam member 50 (Figs. 5 anda? )i Thiscam member" is rotatably mounted upony a stud '51'tth'at is threaded into 'one vertical side wall v21'y of v spondingly .shaped jblock The terminal vend of. .the is curlediilponitself and the camera box 20:

Th'ecam member 50"has asecondperipheral cam surfaceorlobe'SS. "This cam surface 53j engages al follower fo'rmecl` bybending laterally a portion of an arm- 57l This- 'armfls rst bentrlaterally to provide-'an oisetfportion 58; thenlis bent parallel'to'itself t'o 4 555i" A" coil' spring '60;

50,' and-whichhas-itsf'other'end secured: in the vertical Ptented..-N.0v. 9, 1954 `leaf springs y aligned r'ails29 bylmks .'or r-other I-conventional':'connecting'f'means (not.

x A y provide a portion 59;- a'ndthenis bentlaterallyagainktoprovide the follower.A` which' is`coile`d about the stud. 51. andwhihhas oneend en'gagnairecess 61 in'fthecam...

wall 21 ofthe camera box, serves to hold the cam surface 49 against the yoke follower 47. A coil spring 62, which is engaged over a lug 63 formed on the arm 57 and which is secured at its other end to a pin 64 that is fastened in side wall 21 of the. camera box, serves to hold the follower 55 in engagement with the cam surface 53.

Through the follower 47 and spring 60, motion of the slide 28 is transmitted to the cam member 50. Through the cam surface 53, follower 55 and spring `62, motion of the cam member 50 is transmitted to the arm 57. The arm 57 transmits motion tothe rotatable transparent mirror of the range finder as will be described further hereinafter.

The rangender itself is housed within a casing 70 (Figs. 1, 2, 3 and 4) which is secured to the outside of the wall 21 of the camera case or box 20 by screws 71 (Fig. 2). The casing is rectangular in shape.- Access may be had to its interior by removing the lid or cover 73. This lid or cover is secured in position at one side of the casing by screws 74 that threadl into holes 75 in the casing Walls. t

Mounted in that side wall 77 of the rangender casing 70, which is contiguous to the side wall 21 of camera casing 20, is a bolt or bearing member 78 (Figs. 3 and l2). The shank of this bolt or bearing member is externally threaded for part of its length. It is adapted to pass through a hole in the wall 77 of the rangender casing and through an aligned hole 80 in the vertical side wall 21 of the camera case. The head 79 of the bolt seats against the inside face of the wall 77 of the casing 70. A nut 82 threadsk onto the shank of the bolt inside the camera case to hold the head of the bolt tight in the rangender casing and in the-camera box.

Silver-soldered or otherwise secured to the bearing member 78 is a beam 85 which is U-shaped in cross-section. Mounted upon this beam at the free end thereof is a support or bracket 87 which carries a mirror or reiiector 88. l

The bracket or support comprises a metallic stamping which extends in back of the mirror 88. .This support is formed at its base with two forwardly-extending seating portions 89 (Figs. 2, 3, 9 and l0), and has a rearwardly projecting part 90 which is stamped out of the back portion of the sheet and bent down to lie substantially in the plane of the supporting lugs 89. The back portion of the support 87 is coined at three spaced points to form three spaced forwardly-projecting seating bosses 92 (Fig. 11). The mirror 88 is secured to the support 87 by three U-shaped springclips 94, each of which has its free end bent inwardly toward one another. The spring clips are adapted to be engaged over the contiguous edge surfaces of the mirror and its support with the end of one leg of each clip engaging the front face of the mirror and the end of the other leg of .each clip seating in a recess 95 formed in the back of thesupport 87 by the coining of a seat 92. The mirror is thus mounted with a threepoint bearing upon the support 87 and held to the support .under spring tension. Moreover, the clips 94 apply the spring pressure, which holds the mirror on the support, directly in line with the seats 92. A mounting is thereby provided for the mirror which will not transmit strains to the mirror. At the same time, a mounting is provided which permits the mirror to be easily and quickly assembled on its support. No cementing of the mirror to the support is required; and the mess and cost of a cementing operation are obviated.

The support 87 itself is mounted for tiltable adjustment on the U-shaped beam member 85. The side walls of this member are cut away near the outer end thereof to leave only a projecting tongue 97 on which the support 87 is carried. This projecting portion 97 is formed with two hemispherical bosses 98, which are laterally aligned, and which seat in hemispherical sockets stamped in the supporting lugs 89 of support 87. A coil spring 100 is interposed between the rearwardly projecting portion 90 of the support 87 and an arched yoke portion 101 stamped up from the extension 97 of the base portion of beam member 85. The spring is held at its upper end by a lug 102 formed on the center of the arch of yoke member 101. The spring tends to rock the support 87 counterclockwise on the bosses 98, as viewed in Fig. 10. A screw 104, which threads into the rearwardly projecting portion 90 of the support 87 and which engages the top face of the extension 97 of the beam member 85 serves for adjustment of the support 87 angularly on the beam member 4 85. This adjustment is an adjustment useful in manufacture and assembly of the rangender, permitting the plane of the mirror 88 to be positioned so as to eliminate side image.

The bolt or bearing member 78 is bored to have a generally hexagonal shaped bore, as shown in Fig. 12. This bore has three equi-angularly-spaced, generally plane portions 111 and three alternating equi-angularly spaced concave portions 112. Journaled in the bore of the bearing member 78 is a shaft 115 (Fig. 3). This shaft extends at its outside end through the ybolt 78 into the range finder casing 70. Splined and soldered to the end of the shaft, which is inside the casing 70, is a collar 116 and brazed or soldered to this collar 116 is a support 117 for the semi-transparent mirror 118.

This support 117 is formed with a rearwardly bent fan tail portion 119. The mirror 118 is secured to the support 117 by three spring clips 94 which may be identi- ,cal in construction with the spring clips 94 previously described and which engage at their front ends with the face of the mirror and seat at their rear ends in sockets formed by stamping the support 117 to` provide bosses, similar to those of the mirror support 87, against which mirror 118 seats. The mirror support V117 is cut away, as shown in dotted lines 120 in Fig. 3, to permit light to pass through the mirror to the eye-piece of the range nder.

The shaft 115 is heldin engagement with two spaced v plane portions 111 of the bore 110 of bolt 78 by an arcuate leaf spring 113 which seats in a peripheral recess 114 formed in the shaft 115, and which is thereby held against axial movement relative to the shaft. This spring seats at opposite ends v.against two of the arcuate portions 112 of the bore 110. The spring holds the shaft against two of the plane side portions 111 of the bore 110 and serves itself as the third bearing for the shaft,

thus providing a three point bearing mounting for the shaft. This bearing mounting prevents play between the shaft and the bore of bolt 78, and provides a much more accurate mounting for the shaft than would be possible were the bolt provided simply with a cylindrical bore matched as closely as possible in internal diameter to the external diameter of the shaft.` is here required and a better mounting results.

The shaft 115 projects at its inside end through the bolt 78 into the camera box. Secured to the end of the shaft, that projects into the camera box, is a hub member (Fig. 8). This member is fastened to the shaft by a set Screw 126 (Fig. 5). The hub member 125 is riveted to an adjusting arm 127 (Fig. 8) so that it is fixed to said arm near one end thereof. Secured in the other end of this arm 127 isa stud 129 which carries an eccentric 130. The eccentric is formed at one endwith a square head 134, and is held against axial and angular movement reative to the arm by this head and by a spring washer k131 that is riveted to stud 129 at the other endl thereof.- The eccentric engages in an elongated hole 132 formed in the lever arm 57 coaxial with the stud 129. between the lever arm 57 and the hnb 125 disc 135.

The eccentric 130, in conjunction with the follower screw 47, permits of precise angular adjustment of the mirror 118 so as to set themirror correctly so that the infinity point of the range finder may correspond to the is a friction infinity point of the objective of the camera and so that the followers 47 and 55 may contact with the proper portions of the cam surfaces 49 and 53 to achieve the proper movement of the mirror in the focusing adjustment of the objective lens of the camera.

The cam surface 49 is shaped to impart uniform rotary motion to the cam'Stl about the axis of shaft 51 as the objective lens of the camera is moved forward er backward in the focusing of the camera. The cam surface 53 is shaped to impart non-uniform motion to the lever 57. This produces the non-uniform pivotal motion of the mirror 118 required for the different varingly-spaced focus settings of the objective of the camera from irl- No matching interposed l adjustment` of arm 57 relative to'- arm 127 the angular The 'rangefinder casing 70 is completely sealed against t passageof lightexcept-forV the twowindow openings140 and `141 'QF-ig. 2) inits-front -wall-142-f(-Fig. 4) and the openingt 143 in' itsrear-wall-inwhichdhe eye piece-144 is mounted. The eye piece is of conventional construction and includes the eye glass or lens 145. The windows 147 (Fig. 13) are mounted in window grooves 153 in front of cast lugs 148 formed on the front wall. 142 of the rangefinder casing. The windows are held in the window openings by leaf springs 150 which are inserted in the window openings behind the windows and interposed between the windows and the lugs 148. These leaf springs are arcuately curved and have lugs 151 formed on their sides to engage the side edges of the windows to retain the leaf springs against lateral movement. The springs can be readily inserted behind the windows or removed therefrom so that assembly and disassembly of the windows can be made very quickly.

Because of the simple linkage transmitting motion from the lens board of the camera directly to the transparent mirror 11S through the double-lobed cam 50 accuracy and low-costare achieved. These features are enhanced by other features of our rangefinder. Thus, the three point mountings for the mirrors 88 and 118 by means of the spring clips 94 hold the mirrors securely without transmitting strain to them, and establish the plane of each mirror. Each mirror is clipped over the points of its location directly by the three spring clips- The mirrors 118 and 88 carried by shaft 115 and beam 85, respectively, are thereby mounted to be free of the effect of any distortion of the range finder case. The beam is furthermore secured at one end to a bolt 78 which serves not only as a bearing for shaft 115 but passes through the rangefinder case 70 and the camera case to hold the two cases between the beam and the nut 82 that threads onto the bolt. The beam, moreover, can be made of annealed steel because of the simple shape employed. This further increases the rigidity of the construction thereby increasing the accuracy of the rangefinder.

While the invention has been described in connection with a specific embodiment thereof it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thus described our invention, what we claim 1s:

1. In combination, a camera having a bed, a slide slidable on said bed, an objective lens mounted on said slide to be adjustable upon movement of said slide for focusing, a casing having two windows fixed in its front wall one disposed vertically above the other, an observation window fixed in its rear wall, a reflector pivotally mounted in said casing in register with the upper of the two front windows and with said observation window, a relatively fixed reflector mounted in said casing in register with the lower of the two front windows, said pivotally mounted reflector being a semi-transparent mirror, a cam pivotally mounted in said camera and having two lobes, a cam follower engaging one of asid lobes and connected to said slide for movement upon adjustment of said slide, a second cam follower engaging the other of the cam lobes, and means connecting the second cam follower to said pivotally-mounted reflector to pivot said reflector upon movement of said second cam follower, the first cam lobe having its active surface shaped to impart uniform motion to said cam upon movement of the first cam follower, and the second cam lobe having its active surface shaped to impart nonuniform motion to said second cam follower upon movement of the cam.

2. In combination, a camera having an objective lens that is adjustable for focusing, a casing having two windows fixed in its front walk-onedisposed-vertically above the other-,fan observation window fixedin its rear wallin alignment with the upper of the two-:front windows,- a

reflector :pivotally mounted in said tcasing inV register'. with fsaid '.upper rfront window and twith; said observationk window, a; relatively fixed reflector mounted in said icas--V inginregis ter .fwith the lower ofthe two-.front windows,:y the'pivoted reflector beingl semi-transparent, a pivotally-` mounted cam member, a cam follower engaging said cam member and connected to said objective lens to rock said cam upon adjustment of said lens, said cam follower being adjustable to adjust the point of its engagement with said cam member, a second cam member connected to the first cam member to move upon pivotal movement of the first cam member, a second cam follower engaging said second cam member, and an arm carrying said second cam follower, said arm being connected to the pivoted reflector to pivot said reflector upon movement of the second cam follower, and means for adjusting the pivoted reflector angularly relative to said arm.

3. In combination, a camera having an objective lens that is adjustable for focusing, a casing having two windows in its front wall, one disposed vertically above the other, an observation window in its rear Wall in alignment with the upper of the two front windows, a reflector pivotally mounted in said casing in register with said upper front window and with said observation window, a relatively fixed reflector mounted in said casing in register with the lower of the two front windows, said pivoted reflector being semi-transparent, a pivotally mounted cam member, a cam follower engaging said cam member and connected to said objective lens to rock said cam upon adjustment of said lens, said cam follower being adjustable to adjust the point of its engagement with said cam member, a second cam member connected to the first cam member to pivot upon pivotal movement of the first cam member, a second cam follower engaging said second cam member, an arm carrying said second cam follower, a second arm secured to said pivoted reflector, and means connecting said two arms so that movement of the first-named arm is transmitted to the second-named arm and thereby to said pivoted reflector, said last-named connecting means being adustable to adjust said pivoted reflector about its pivotal axis independently of the first-named arm.

4. In combination, a camera having an objective lens that is adjustable for focusing, a casing having two windows in its front wall, one disposed vertically above the other, an observation window in its rear wall in alignment with the upper of the two front windows, a reflector pivotally mounted in said casing in register with said upper front window and with said observation window, a relatively fixed reflector mounted in said casing in register with the lower of the two front windows, said pivoted reflector being semi-transparent, a pivotally mounted cam member, a cam follower engaging said cam member and connected to said objective lens to rock said cam upon adjustment of said lens, said cam follower being adjustable to adjust the point of its engagement with said cam member, a second cam member connected to the first cam member to pivot upon pivotal movement of the first cam member, a second cam follower engaging said second cam member, an arm carrying said second cam follower, a second arm secured to said pivoted reflector, and means connecting said two arms so that movement of the first-named arm is transmitted to the second-named arm and thereby to said pivoted reflector, said last-named connecting means comprismg an adjustable eccentric member secured to one of said arms and engaging in an elongated hole in the other arm whereby upon adjustment of said eccentric member said pivoted reflector is adjusted on its pivotal axis independently of said first-named arm.

References Cited in the tile of this patent UNITED STATES PATENTS Number Name Date 948,216 Fluke Feb. 1, 1910 1,261,643 Stout Apr. 2, 1918 2,154,958 Polhemus Apr. 18, 1939 (Other references on following page) Number 7 UNITED STATES PATENTS Name Date Liebmann Ian. 9, 1940 Allen Mar. 12, 1940 Liebmann Jan. 28, 1941 Cazin May 20, 1941 Steiner Nov. 4, 1941 Brownscombe Dec. 30, 1941 Number Number Name Date Liebmarm et a1. Aug. 18, 1942 Schwartz et a1 May 29, 1945 FOREIGN PATENTS Country Date Germany Feb. 18, 1933 Great Britain Mar. 30, 1933 Germany June 15, 1933 

